package rulecache

import (
	"context"
	"fmt"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

// activeRulesQuery resolves condition_source_device_id/target_device_id (FKs
// into devices.id) to devices.external_id, since every other part of the
// platform (MQTT, Redis, gRPC) keys devices by their external ID, not
// PostgreSQL's internal bigserial ID.
const activeRulesQuery = `
SELECT
	r.id AS rule_id,
	r.zone_id AS zone_id,
	src.external_id AS source_external_id,
	tgt.external_id AS target_external_id,
	r.condition_sensor_type AS condition_sensor_type,
	r.condition_operator AS condition_operator,
	r.condition_value AS condition_value,
	r.action_type AS action_type,
	r.action_params AS action_params
FROM automation_rules r
JOIN devices src ON src.id = r.condition_source_device_id
JOIN devices tgt ON tgt.id = r.target_device_id
WHERE r.is_active = true
`

type PostgresFetcher struct {
	pool *pgxpool.Pool
}

func NewPostgresFetcher(pool *pgxpool.Pool) *PostgresFetcher {
	return &PostgresFetcher{pool: pool}
}

func (f *PostgresFetcher) FetchActiveRules(ctx context.Context) ([]Row, error) {
	dbRows, err := f.pool.Query(ctx, activeRulesQuery)
	if err != nil {
		return nil, fmt.Errorf("query active rules: %w", err)
	}
	rows, err := pgx.CollectRows(dbRows, pgx.RowToStructByName[Row])
	if err != nil {
		return nil, fmt.Errorf("scan active rules: %w", err)
	}
	return rows, nil
}